From 3653e9333819af75fdbac093624fca7232577adf Mon Sep 17 00:00:00 2001
From: krunalchande <krunalchande@gmail.com>
Date: Tue, 23 Dec 2014 16:14:50 -0500
Subject: [PATCH] fix bug in dual feasibility check. We want dual variables <
 0.

---
 gtsam_unstable/nonlinear/LCNLPSolver.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gtsam_unstable/nonlinear/LCNLPSolver.cpp b/gtsam_unstable/nonlinear/LCNLPSolver.cpp
index 3a2f017f7..0fa840ab8 100644
--- a/gtsam_unstable/nonlinear/LCNLPSolver.cpp
+++ b/gtsam_unstable/nonlinear/LCNLPSolver.cpp
@@ -40,8 +40,9 @@ bool LCNLPSolver::isDualFeasible(const VectorValues& duals) const {
     Key dualKey = inequality->dualKey();
     if (!duals.exists(dualKey)) continue; // should be inactive constraint!
     double dual = duals.at(dualKey)[0];   // because we only support single-valued inequalities
-    if (dual < 0.0)
+    if (dual > 0.0) {   // See the explanation in QPSolver::identifyLeavingConstraint, we want dual < 0 ?
       return false;
+    }
   }
   return true;
 }